[Feature request] Tag support

[noraj]

Very similar to mkdocs/mkdocs#1828.

Feature idea

The idea is that Hexo has already tag support for tags in frontmatter.

This generate a page like https://hexo.example.org/tags/security/ referencing all pages containing this page. But each post will also have some tags link #security.

Example:

There is also a tag cloud support in the API so some theme like hueman are able to make some great looking tag clouds widget:

So adding support for this theme would be easy as the feature already exist in hexo, is already available in other themes (so there are examples).

Why this would be a great feature?

see mkdocs/mkdocs#1828